John's Background Switcher - Switch backgrounds to trending imgur, reddit, tumblr threads
CPU-Z - CPU-Z is a freeware that gathers information on some of the main devices of your system : Processor name and number, codename, process, package, cache levels.
Muzei - Muzei is a live wallpaper that gently refreshes your home screen each day with famous works of art.
Speccy - Speccy - find the details of your computer's specs. Great for spotting issues or finding compatible upgrades. Download the latest version free.
Variety Wallpaper Changer - Variety is a wallpaper changer for Ubuntu which is featureful, yet slim and very easy to use.
AIDA64 - AIDA64 is a system information, diagnostics and benchmarking solution for Windows PC.